1.2.1. Choosing a compset

When setting up a new case one of the first choices to make is which “component set” (or compset) to use. The compset refers to which component models are used as well as specific settings for them. We label the different types of compsets with a different letter of the alphabet from “A” (for all data model) to “X” (for all dead model). The compsets of interest when working with CLM are the “I” compsets (which contain CLM with a data atmosphere model and a stub ocean, and stub sea-ice models), “E” and “F” compsets (which contain CLM with the active atmosphere model (CAM), prescribed sea-ice model, and a data ocean model), and “B” compsets which have all active components. Below we go into details on the “I” compsets which emphasize CLM as the only active model, and just mention the two other categories.

To run CLM coupled to CAM (“E” or “F” compsets) or fully coupled (“B compsets) you need to be running CLM from a CESM checkout rather than a CTSM checkout (see A CTSM versus a CESM checkout).

When working with CLM you usually want to start with a relevant “I” compset before moving to the more complex cases that involve other active model components. The “I” compsets can exercise CLM in a way that is similar to the coupled modes, but with much lower computational cost and faster turnaround times. Compsets coupled to data atmosphere and stub ocean/sea-ice (“I” compsets)

Supported CLM Configurations are listed in Table 1-1 for the Scientifically Supported compsets (have been scientifically validated with long simulations) and in Table 1-2 for the Functionally Supported compsets (we’ve only checked that they function).

Here is the entire list of compsets available.

CESM compsets

Note that using the “-user_compset” option even more combinations are possible. To get a list of the compsets use the “query_config” command as follows:

$CTSMROOT/cime/scripts/query_config --compsets clm Compsets coupled to active atmosphere with data ocean

CAM compsets are compsets that start with “E” or “F” in the name. They are described more fully in the scripts documentation or the CAM documentation. “E” compsets have a slab ocean model while “F” compsets have a data ocean model. Fully coupled compsets with fully active ocean, sea-ice, and atmosphere

Fully coupled compsets are compsets that start with “B” in the name. They are described more fully in the scripts documentation. Conclusion to choosing a compset

We’ve introduced the basic type of compsets that use CLM and given some further details for the “standalone CLM” (or “I” compsets). The $CTSMROOT/cime_config/config_compsets.xml lists all of the compsets and gives a full description of each of them. In the next section we look into customizing the setup time options for compsets using CLM.